The CSS interface holds useful CSS-related methods. No object
this interface are implemented: it contains only static methods
therefore is a utilitarian interface.

The CSSKeywordValue interface of the the CSS Typed Object Model
creates an object to represent CSS keywords and other identifiers.

The CSSMathValue interface of the CSS Typed Object Model API
base class for classes representing complex numeric values.

The CSSNamespaceRule interface describes an object representing
single CSS `web.@namespace` at-rule. It implements the `css.CSSRule`
with a type value of 10 (CSSRule.NAMESPACE_RULE).

The CSSNumericValue interface of the CSS Typed Object Model API
operations that all numeric values can perform.

The CSSPositionValue interface of the the CSS Typed Object Model
represents values for properties that take a position, for example

The CSSPrimitiveValue interface derives from the `css.CSSValue`
and represents the current computed value of a CSS property.

The CSSPseudoElement interface represents a pseudo-element that
be the target of an event or animated using the Web Animations
Instances of this interface may be obtained by calling `web.Element.pseudo()`.

The CSSRule interface represents a single CSS rule. There are
types of rules, listed in the Type constants section below.

The CSSStyleDeclaration interface represents an object that is
CSS declaration block, and exposes style information and various
methods and properties.

CSSStyleRule represents a single CSS style rule. It implements
`css.CSSRule` interface with a type value of 1 (CSSRule.STYLE_RULE).

The CSSStyleSheet interface represents a single CSS stylesheet,
lets you inspect and modify the list of rules contained in the

The CSSStyleValue interface of the the CSS Typed Object Model
is the base class of all CSS values accessible through the Typed
API. An instance of this class may be used anywhere a string
expected.

The CSSUnitValue interface of the CSS Typed Object Model API
values that contain a single unit type. For example, \"42px\"
be represented by a CSSNumericValue.

The CSSUnparsedValue interface of the CSS Typed Object Model
represents property values that reference custom properties.
consists of a list of string fragments and variable references.

The CSSValue interface represents the current computed value
a CSS property.

The CSSValueList interface derives from the `css.CSSValue` interface
provides the abstraction of an ordered collection of CSS values.

The CSSVariableReferenceValue interface of the CSS Typed Object
API allows you to create a custom name for a built-in CSS value.
object functionality is sometimes called a \"CSS variable\" and
the same purpose as the `web.var()` function. The custom name
begin with two dashes.